Benthos are organisms that live a. on the surface of water. b. throughout the water column. c. on the ocean floor. d. in shallow water.

d. making up measurements to record.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.